The aim of this work is to understand the manner in which the production of acetylcholinesterase is regulated in Drosophila. We are attracted to this system because it lends itself to sophisticated genetic manipulations, is biochemically accessible, and exhibits a tissue specific pattern of expression. Thus, questions about differential gene expression during development can be approached using this system. Our work for the next year will involve continued characterization of the multiple forms of the enzyme, isolation and characterization of conditional mutations at the nucleic acid (DNA and mRNA) levels and at the level of the protein (kinetic and antigenic properties) as well as at the level of gross phenotype. In addition to standard genetic and biochemical techniques, recombinant DNA technology will be utilized in the exploitation of this system.